1. Field of the Invention
The present invention generally relates to automobile exhaust pipes, and more particularly to an exhaust pipe capable of producing appropriate pressure to assist engine torque output when the engine is running at a low speed and expediting the waste gas to be discharged from an automobile when the engine is running at a high speed, so as to enhance the operating performance of automobile engines.
2. Description of the Related Art
In the operating principle of an automobile, an engine nebulizes a fuel and mixes the nebulized fuel with air, so as to create an explosion in a cylinder, and the pressure of expansion is converted into a rotary force to drive the wheels to rotate. The mainstream of automobiles is a 4-cylinder engine with a design of driving the pistons repeatedly to move up and down for two times. In other words, four actions including an air inhaling, a compression, an expansion, and a discharge are preformed when the engine rotates twice, and the ignition is done by electric sparks. The total volume for the pistons in the cylinders to move up and down is called exhaustion capacity, which is also an index of an engine power. In normal conditions, if the engine is running at a low speed, then the exhaust pipe will produce an appropriate discharge pressure to assist the engine torque output; and if the engine is running at a high speed, the exhaust pipe will expedite the exhaustion to enhance the engine operating performance of an automobile.